Leases - Other lease information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	$ 480	$ 483	$ 1,409	$ 1,509
Operating cash flows from finance leases	4	5	13	17
Financing cash flows from finance leases	$ 15	$ 13	$ 43	$ 41
Weighted average remaining lease term
Operating leases	1 year 4 months 24 days		1 year 4 months 24 days		1 year 1 month 6 days
Finance leases	3 years 3 months 18 days		3 years 3 months 18 days		4 years
Weighted average discount rate
Operating leases	6.82%		6.82%		7.19%
Finance leases	7.75%		7.75%		7.75%